brook (nachal, 'aphiq, ye'or, mikhal; cheimarrhos):
In Palestine there are few large streams. Of the smaller ones many flow only during the winter, or after a heavy rain. The commonest Hebrew word for brook is nachal, which is also used for river and for valley, and it is not always clear whether the valley or the stream in the valley is meant (Numbers 13:23; Deuteronomy 2:13; 2 Samuel 15:23). The Arabic wady, which is sometimes referred to in this connection, is not an exact parallel, for while it may be used of a dry valley or of a valley containing a stream, it means the valley and not the stream. 'Aphiq and ye'or are translated both "brook" and "river," ye'or being generally used of the Nile (Exodus 1:22, etc.), though in Daniel 12:5-7, of the Tigris. Cheirnarrhos, "winter-flowing," is applied in John 18:1 to the Kidron. Many of the streams of Palestine which are commonly called rivers would in other countries be called brooks, but in such a dry country any perennial stream assumes a peculiar importance.
Alfred Ely Day